In a three-phase motor control apparatus, a shunt resistor is connected to an output transistor which drives a coil of each phase, a current flowing in the shunt resistor is converted into a voltage, and the level of a current flowing in the coil of each phase is controlled by comparing the converted voltage and a reference voltage.
Since a current flows in coils of two or more phases at the same time in a 180° conduction type three-phase motor, a high current resulting from combining currents flowing in the coils of the respective phases flows in the shunt resistor, and an amount of heat generated in the shunt resistor increases. Therefore, the related-art IC chip having an output transistor formed therein does not have a shunt resistor mounted therein, and the shunt resistor is mounted outside of the IC chip. As a result, there is a problem that the cost of the three-phase motor control apparatus increases.